Taximeters

ABSTRACT

A taximeter having a mechanical mechanism which operates a control element to rotate the control element at a rate proportional to the distance travelled by a taxi, if the speed of the taxi is greater than a predetermined value, or otherwise to rotate the element at a constant rate, the element having associated therewith a transducer for generating a pulse train of frequency corresponding to the speed of rotation of the element and electronic counter and display means being provided to count the pulses of the pulse train and to display a taxi fare in accordance with a count of the pulses over the time of a taxi journey.

United State S Patent [1 1 Hart [ Dec. 31, 1974 [54] TAXIMETERS3,553,442 1/1971 Weisbart 235/92 3,703,985 11 1972 B 235 30 R [75]Invent: Franc'sghseph North Balwyn, 3,764,782 10i1973 5522352115 et al23si30 R Australia [73] Assignee: Martin Taximeters (Aust.) Pty., Ltd. my EXamiI1r-RiChard Wilkinson Assistant Examiner-Vit W. Miska [22] Filed:May 1973 Attorney, Agent, or Firm-McGlew and Tuttle [2]] Appl. No.:357,780

[57] ABSTRACT [30] Foreign Appli atio P i it D t A taximeter having amechanical mechanism which May 10 1972 Australia 8917/72 operates acontrol element to rotate the control element at a rate proportional tothe distance travelled 521 US. Cl. .L .235/30 R 235/45 by a taxi if theSpeed of the mi is greater than a P 51 Int. Cl. G07 b 13/00 determinedvalue, or Otherwise to rotate the element 5 Field of Search 23523012 3345 at a constant rate, the element having associated therewith atransducer for generating a pulse train of [56] References Citedfrequency corresponding to the speed of rotation of the element andelectronic counter and display means UNITED STATES PATENTS beingprovided to count the pulses of the pulse train 3,157,352 11/1964Caywood 235/45 and to display a taxi fare in accordance with a Count Z::1 of the pulses over the time of a taxi journey 3:512:70o 5/l972 235/30R 14 Claims, 5 Drawing Figures Ami/W!!! fiffl/ Wff W12 flfJ/f Wl'fil/f/{My Mf/fl/fl ,lfl/jfffff/ 17 aw zb w 14 1mm fiwz/wfz/wf w 43 w VafillllHit 3 \iiii iiti WWI/M! iii flaw /7Vf fl/V/ff KIM 7Z7 [lfl/V/Y [flfl/V/Z[WM f L L /2- l L l W4 W1 W1 fif/Wfif/ JIM/[1 fif/dfif/ flff/fl/F i i iL74 2 i? [7 37 A7 a?! H 1 H -?7 i lid/Z6 'f/M/f/fiV/Z [[A [f M J/f/Al/fi/J/[fl fi/JP/l/ SHEET 2 [1F 3 at u L L $2 W4 W W4 mwm/ FIG. 4. w w i 0i i a 24 I2 BACKGROUNDOF THE INVENTION 1. Field of the Invention Thisinvention relates to taxi meters.

2. Description of Prior Art Taxi meters of one kind in common useutilise a mechanical device which has a rotatable member which, when thevehicle is stationary or moving at less than a predetermined speed, isdriven at a preselected rate but which is coupled, when the vehicle ismoving at more than the predtermined speed, to be driven at a rate whichis proportional to the vehicle speed. Suitable mechanical means isprovided, operated by this member to operate a mechanical farechargerecorder which, when the vehicle is stationary or moving at less thanthe predetermined speed, records a fare charge which is proportional totime and when the vehicle is moving at at more than the predeterminedspeed, records a distance travelled fare charge.

Taxi meters of the above kind, while being generally satisfactory in userequire adjustment and continual maintenance in order to preserve theiraccuracy under operating conditions. This is particularly necessary inrespect of the fare charge recorder. Proposals have been made to avoidthis problem by employing wholly electronic devices but these tend tointroduce further difficulties in that they are oftenprone to electricalinterference which causes wrong fare computations'An object of theinvention is therefore to provide a taxi meter which avoids, at least inpart, the above difficulties.

BRIEF SUMMARY OF THE INVENTION According to the present invention thereis provided a taxi meter having a rotatable control element, means fordriving said element at a constant preselected rate, means for drivingthe element at a rate dependent upon the speed of a vehicle to which thetaxi meter is affixed and clutch means for selectively coupling eitherof said drive means to said element so that the element is driven, whenthe vehicle is moving at more than a preselected speed, by said secondmeans, and when the vehicle is stationary .or moving at less than saidpreselected speed, by said first means, said device further includingtransducer means coupled to said element for producing an electricalsignal pulse train representative of the speed of rotation of theelement and electronic counter and display means for counting the pulsesof said train and displaying a fare value proportional to the number ofpulses counted. Preferably the lastmentioned means includes pulsemultiplier means for multiplying the pulses by a preselected valueproportional to a preselected fare rate.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING:

One embodiment of the invention is now described in detail withreference to the accompanying drawing, in which:

FIG. 1 is a partly schematic view of mechanical parts of the taxi meter;

FIG. 2 is across-section on the line 2-2 in FIG. 1;

FIG. 3 is a diagram illustrating the manner of organisation ofelectronic counter and display means forming part of the taximeter;

FIG. 4 is an electrical circuit diagram of part of the counter anddisplay means of FIG. 3; and

FIG. 5 is an electrical circuit diagram of another part of the counterand display means of FIG. 3.

DETAIL DESCRIPTION Referring firstly to FIG. 1, the taxi meter includesa mechanical device 11 having a gear train 50 which is coupled to thespeedometer drive cable from the engine gear box of a taxi 52, to bedriven by the gear box.

The gear train 50 has an output shaft 54 which is driven by the geartrain at a rate proportional to the speed at which the vehicle istravelling. An electric motor 56 drives a second gear train 58, theoutput shaft 60 of gear train 58 being driven at a constant speed.

Shafts 54, 60 are coupled to a clutch 62 which is itself coupled todrive a third gear train 64 from a gear 62a on the clutch. Gear train64, in turn, drives an output shaft 66 of device 11 to which is attacheda five-lobe cam 68, of a transducer 12.

Clutch 62 is of a kind operating to drive gear 62a at a speed equal tothe speed of whichever one of shafts 54 and 60 is rotating at the fasterrate.

The drive from motor 56 is such as to tend to drive output shaft 66 at aconstant speed of about one revolution every 2 minutes whereas the drivefrom the speed ometer cable is such as to tend to drive the shaft at aspeed approximately two revolutions to the mile travelled by the taxi.Accordingly, when the taxi is stationary, the output shaft 66 of device11 will be turned at one revolution every 2 minutes, but when thevehicle speed reaches a predetermined level it will instead be driven ata rate of approximately two revolutions to the mile.

Transducer 12 includes a cam follower 70 of spring steel which isattached at one end 70a to a fixed part (not shown) of the taximeter sothat the free end 70b is biased resiliently radially inwardly of the camfollower.

An operating arm 72 also of spring steel is attached at one end 720 to afixed part of the taxi meter and the free end carries a roller 74 whichis biased against cam follower 70. An actuating member 76 ofa microswitch 78 is positioned adjacent to arm 72. As shaft 66 turns camfollower 70 is flexed upwardly and then downwardly, as viewed in FIG. 2,each time end 70b thereof passes over a lobe 68a of cam 68. Roller 74thus is also moved upwardly and downwardly, because the roller is biasedagainst the cam follower, so that up and down flexing of arm 72 results.This flexing of arm 72 causes the arm to press against member 76 tooperate micro switch 78 each time the end 70b of the cam follower movesdownwardly. Micro switch 78 is thus operated five times for everyrevolution of shaft 66.

Switch 78 is of the single pole double throw type and is coupled into anelectric circuit 80 (FIG. 5) forming part of transducer 12. Thus, amovable contact 7811 of the switch is connected to an earthed terminalof an electric power supply (not shown) by a conductor 82.

pulses being proportional to the speed of rotation of output shaft 66.

Output lines 88, 90 from circuit 80 are connected to a pulse shapingcircuit 13. This includes a flip-flop 92 having two inverters 94, 96which receive input pulses on lines 88, 90 and produce corresponding,shaped, pulses on output line 98, these shaped pulses having cleanleading and trailing edges suitable for operation of subsequent integersof the taxi meter. Line 98 is coupled to the base of a transistor 100which is connected into a switching circuit 102. Circuit 102 provides apulse train output on an output line 104 which is connected to a pulsemultiplier 14.

Output line 104 couples to a first differentiating circuit 110 of pulsemultiplier 14. This circuit includes a capacitor 112 coupled, at oneside, to line 104 and a resistor 114 connected between the other side ofthe capacitor and the earthed terminal of the power supply. Output fromcircuit 110 is taken on a conductor 116 coupled to the junction betweenthe capacitor and resistor. conductor 116 is connected to the inputterminal of an inverter 118, and the output terminal of this inverter iscoupled, via a conductor 120 and a resistor 122 to the supply rail ofthe power supply. Differentiating circuit 110 operates to render pulsesfrom circuit 13 of constant short duration. In this respect it will beappreciated that pulses generated by switch 78 will be of duration equalto the inverse of the pulse frequency, and will thus vary in durationover a considerable range as the speed of taxi 52 changes. Thisvariation in pulse duration, which is considerable, is removed bydifferentiating circuit 110. Inverter 118 and resistor 122 are connectedto produce, from circuit 110, output pulses on conductor 120. For everypulse applied on line 104, then, there is generated on conductor 120, asingle pulse of constant duration.

Multiplier 14 includes four further differentiating cir cuits 124, 126,128, 130. Each of these circuits is identical to circuit 110. These arecoupled to line 104, via separate delay circuits 132, 134, 136, 138,which each comprise a capacitor 140 coupled at one end to line 104 and aresistor 142 connected between the other side of the capacitor and theearthed terminal of the power supply. Outputs from the delay circuits132, 134, 136, 138 are taken, via respective inverters 142, 144, 146.148 and applied to respective ones of the differentiating circuits 124,126, 128, 130. Outputs from the differentiating cirucits are applied torespective further inverters 150, 152, 154, 156. Conductors 158, 160,162, 164 couple outputs from these inverters to a common conductor 166which is coupled to conductor 120 and to resistor 122.

The delay circuits 132, 134, 136, 138 have progressive delays soarranged that a pulse applied to these on line 104 will generate on eachconductor 158, 160, 162, 164 a separate pulse of duration equal to thatof a pulse produced on conductor 120, but with progressively increasingtime delays after the pulse on line 120 appears. As described in detailhereinafter conductors 158, 160, 162, 164 can be selectively interruptedby assuming that not interruption is effected pulse multiplier 14produces on conductor 166, for each pulse applied on line 104, a seriesof five equitime spaced pulses of short duration.

Conductor 166 of pulse multiplier 14 is connected via a line 108 to aunits decade counter 17. This operates to provide, on output lines 170,a binary coded output advancing one count for every pulse applied to thecounter. This output is applied to a decoder 22 connected to drive aseven segment cents display device 27.

Display device 27 is thus operated to successively display numerals O to9 in repeated sequences, the numeral displayed advancing one count foreach pulse applied to counter 17. At each tenth count a pulse isdelivered on an output line 172 from counter 17.

Three further decade counters 18, 19 and 21 are provided. Counter 18receives pulses on line 172 and on each tenth pulse delivers an outputon an output line 176 thereof. Counter 19 receives pulses on line 176and, at each tenth pulse, delivers a single pulse on an output line 178therefrom. Counter 21 receives input pulses from line 178. The counters18, 19 and 21 have output lines 174, 180, 182 which couple to respectivedecoders 23, 24 and 26. The counters 18, 19, 21 operate in an analogousmanner to counter 17 producing binary coded outputs on lines 174, 180,182 which advance one count for each pulse applied thereto. The decoders23, 24, 27 likewise operate in an analogous manner to decoder 22, eachadvancing the displayed numeral of an associated display device 28, 29,31 on' count for each pulse applied to the respective counter 18, 19 or21. Counters 18, 19, 21 comprise, respectively, a tens of cents counter,a dollars counter and a tens of dollars counter.

The taxi meter is operated by a switch (not shown) which operates tocouple the power supply to the electrical parts of the meter. Thisswitch might, for example, be coupled to the usual taxi meter HlRE andNOT FOR HIRE indicator mechanism. When switching on is effected, it is,of course, necessary to operate the display devices 27 to 31 so thatthese display the correct flag fall. This is effected by a preset andreset pulse generator 15 in conjunction with a pre set code circuit 32.

Generator 15 includes a transistor 200 having its collector coupled tothe power supply rail via a resistor 202, and its emitter coupled toearth terminal of the power supply via a resistor 204. The base ofthetransistor is coupled, via a resistor 206, to the junction 215 between aseries connector resistor 208 and an earthed capacitor 210. Resistor 208and capacitor 210 are connected between the supply rail and earthedterminal of the power supply. Two inverters 212, 214 are coupledrespectively from the collector and emitter of transistor 200 to acommon line 216, the connection between the emitter and inverter 214being via a resistor 218.

Line 216 is coupled through two parallel differentiating and time delaycircuits 220, 222, each comprising a capacitor and resistor, to separaterespective inverters 224, 226. The output from inverter 224 is connectedvia an output line 228 to conductor 166 of pulse multiplier 14 and thusto line 108. The output terminal of inverter 226 is connected to aconductor 230 and also, via a further inverter 232, to a conductor 234.

When the operating switch for the taxi meter is operated, the powersupply is applied across the earthed terminal thereof and the supplyrail thereof. This causes the voltage at the junction 215 to rise at apredetermined rate. The transistor 200 and inverters 212, 214 operatetogether as a Schmitt trigger circuit which rapidly switches transistor200 when the voltage at jucntion 215 reaches a sufficient value. Thisthus causes a rapid rise of the voltage on line 216, the rise occurringafter a time delay from switching on of the taxi meter. The time delayis made sufficient to ensure that other parts of the electric circuitare in stable operation at the time of voltage increase on line 216.Circuit 220 and inverter 224 operate to provide, from this voltageincrease, an output pulse which is applied to line 108 via conductor228. Likewise, inverters 226 and 232 operate in conjunction with circuit222to provide output pulses on lines 230 and 234.

Line 234 is coupled to decade counter 19, 21 so that the pulse appliedthereon resets these and the associated display devices 29, 31 to zero.The pulses applied on lines 108 and 230 from generator operate to presetthe decade counters l7, l8 and the associated display devices so thatdisplay devices 17, 18 display a preselected initial fare charge. Thisinitial fare charge is selected by means of the preset code circuit 32which operates to bridge selected ones of four binary-code inputterminals 240 of each counter 17, 18 to the line 230. The bridging isarranged such that the pulse on line 230 is applied to the selectedterminals 240 so as to represent, in binary code, the numerals desiredto be displayed in the display devices 27, 28.

Circuit 32 is formed as a plug-in printed circuit and also includes plugconnections which co-operate to completeonly desired ones of theconductors 158, 160, 162, 164. It is thus possible to easily change thedesired initial presetting of counters l7, l8 and to change the numberof pulses appearing on line 108, for each pulse applied to pulsemultipler 14, by unplugging circuit 32 and replacing it with anotherhaving a desired initial display coding for terminals 240 and a desiredselection of pulse miltiplication.

In use of the taxi meter, pulses from transducer 12 are applied to pulseshaper 13 as a pulse train which, when the taxi is at standstill, is ata predetermined constant rate and, when the taxi is moving at more thana predetermined speed, are at a rate proportional to distance travelled.These pulses are shaped in pulse shaper l3, multiplied in multiplier 14as desired by one, two, three, four or five according to the selectedcompletion of conductors 158, 160, 162, 164 and then passed to thecounters to operate the display devices to record the taxi fare. Theselection of a desired pulse multiplication rate is made together withselection of gear ratios in gear trains 50, 58, 64 to give a desiredrate of fare changing.

The taxi meter has been found to be reliable in use because the initialpulse train representing the fare is not generated in a manner which isprone to electrical interference as is the case when the mechanicaldevice 11 in replaced by an electronic pulse generator. On the otherhand, the electronic part of the apparatus is free from theaforementioned disadvantages of mechanical computation mechanisms andrequires little maintenance is use. The electrical part of the meter canbe constructed using readily available components. For example, counters17, 18 may comprise commercially available integrated circuits type 9310whilst counters 19, 21 may comprise integrated circuits type 7490.

The described taxi meter has been advanced merely by way of explanationand many modifications may be made thereto with the spirit and scope ofthe appended claims.

We claim;

1. A taxi meter having a rotatable control element, means for drivingsaid element at a constant preselected rate, means for driving theelement at a rate dependent upon the speed of a vehicle to which thetaxi meter is affixed and clutch means for selectively coupling eitherof said drive means to said element so that the element is driven, whenthe vehicle is moving at more than a preselected speed, by said secondmeans, and when the vehicle is stationary or moving at less than saidpreselected speed, by said first means, said device further includingtransducer means coupled to said element for producing an electricalsignal pulse train representative of the speed of rotation of theelement and electronic counter and display means for counting the pulsesof said train and displaying a fare value proportional to the number ofpulses counted.

2. A taxi meter as claimed in claim 1, wherein said counter and displaymeans includes pulse multiplier means for multiplying the pulses of saidpulse train by a preselected value proportional to a preselected farerate.

3. A taxi meter as claimed in claim 2, wherein said pulse multipliermeans includes a plurality of pulse generators each operable to produce,from a pulse applied to the pulse multiplier means, a separate singlepulse, the pulse generator means including time delay means whereby thesaid pulses generated thereby are generated as a sequence ofequi-time-spaced pulses upon each application of a pulse to said pulsemultiplier means.

4. A taxi meter as claimed in claim 3, wherein coupling means isprovided for selectively coupling at least some of said pulse generatorsto an output of said pulse multiplier means.

5. A taxi meter as claimed in claim 4, wherein said coupling meanscomprises a removable plug-in circuit board having printed thereonparticular electrical connections providing said selective coupling,whereby said pulse multiplier means can be adapted for differentmultiplication rates by replacement of the circuit board.

6. A taxi meter as claimed in claim 1, wherein said transducer meansincludes a switch coupled to cam follower means, said cam follower meansincluding a lobed cam affixed to said element whereby the switch isoperated at least once for each revolution of said element.

7. A taxi meter as claimed in claim 6, wherein said switch is adouble-throw switch having a fixed contact which alternates betweenconnection to two fixed contacts as the switch is operated, said fixedcontacts being coupled to one terminal of an electrical power supply andthe fixed contacts being affixed to the other terminal thereof, wherebythe electrical potential of the fixed contacts alternates as operationof the switch is effected, whereby to generate said train of pulses.

8. A taxi meter as claimed in claim 7, including a pulse shaping circuitinterconnected between said transducer means and said pulse multipliermeans, said pulse shaping circuit including an electrical switchingcircuit which receives outputs from said fixed switch contacts wherebythe pulses of said pulse train are shaped by alternate switching of saidswitching circuit, and are of duration substantially equal to the timeof switching of the switch at either of its positions.

9. A taxi meter as claimed in claim 8 wherein said pulse multipliermeans includes differentiating means by said pulse multiplier means issubstantially less than the duration of pulses applied thereto.

10. A taxi meter as claimed in claim 9 including preset and reset pulsegenerator means which operate to reset said counter and display meanswhen the taxi meter is switched on.

11. A taxi meter as claimed in claim 10, wherein said preset and resetpulse generator means includes preselector means for causing at leastone flagfall counter of said counter and display means to operateassociated display means of the counter and display means to display apredetermined fare indication upon switching on of the taxi meter.

12. A taxi meter as claimed in claim 11, wherein at least one of thesaid counters is provided with binary coded input terminals whichcan beselectively coupled to a presetting pulse generator indluded in saidpreset and reset pulse generator means to cause said at least oneflagfall counter to generate an output resulting in display, in theassociated display means, of said predetermined fare indication.

13. A taxi meter as claimed in claim 12, wherein said presetting pulsegenerator comprises means to generate a preset pulse, as the taxi meteris turned on, and said preselector means includes electric connectormeans on a removable plug-in board which couples selected ones of saidbinary coded input terminals to receive said preset pulse.

14. A taxi meter as claimed in claim 13 wherein said removable plug-inboards are formed as a single unit. =k

1. A taxi meter having a rotatable control element, means for drivingsaid element at a constant preselected rate, means for driving theelement at a rate dependent upon the speed of a vehicle to which thetaxi meter is affixed and clutch means for selectively coupling eitherof said drive means to said element so that the element is driven, whenthe vehicle is moving at more than a preselected speed, by said secondmeans, and when the vehicle is stationary or moving at less than saidpreselected speed, by said first means, said device further includingtransducer means coupled to said element for producing an electricalsignal pulse train representative of the speed of rotation of theelement and electronic counter and display means for counting the pulsesof said train and displaying a fare value proportional to the number ofpulses counted.
 2. A taxi meter as claimed in claim 1, wherein saidcounter and display means includes pulse multiplier means formultiplying the pulses of said pulse train by a preselected valueproportional to a preselected fare rate.
 3. A taxi meter as claimed inclaim 2, wherein said pulse multiplier means includes a plurality ofpulse generators each operable to produce, from a pulse applied to thepulse multiplier means, a separate single pulse, the pulse generatormeans including time delay means whereby the said pulses generatedthereby are generated as a sequence of equi-time-spaced pulses upon eachapplication of a pulse to said pulse multiplier means.
 4. A taxi meteras claimed in claim 3, wherein coupling means is provided forselectively coupling at least some of said pulse generators to an outputof said pulse multiplier means.
 5. A taxi meter as claimed in claim 4,wherein said couplIng means comprises a removable plug-in circuit boardhaving printed thereon particular electrical connections providing saidselective coupling, whereby said pulse multiplier means can be adaptedfor different multiplication rates by replacement of the circuit board.6. A taxi meter as claimed in claim 1, wherein said transducer meansincludes a switch coupled to cam follower means, said cam follower meansincluding a lobed cam affixed to said element whereby the switch isoperated at least once for each revolution of said element.
 7. A taximeter as claimed in claim 6, wherein said switch is a double-throwswitch having a fixed contact which alternates between connection to twofixed contacts as the switch is operated, said fixed contacts beingcoupled to one terminal of an electrical power supply and the fixedcontacts being affixed to the other terminal thereof, whereby theelectrical potential of the fixed contacts alternates as operation ofthe switch is effected, whereby to generate said train of pulses.
 8. Ataxi meter as claimed in claim 7, including a pulse shaping circuitinterconnected between said transducer means and said pulse multipliermeans, said pulse shaping circuit including an electrical switchingcircuit which receives outputs from said fixed switch contacts wherebythe pulses of said pulse train are shaped by alternate switching of saidswitching circuit, and are of duration substantially equal to the timeof switching of the switch at either of its positions.
 9. A taxi meteras claimed in claim 8 wherein said pulse multiplier means includesdifferentiating means one such means being associated with each pulsegenerator means whereby the duration of pulses produced by said pulsemultiplier means is substantially less than the duration of pulsesapplied thereto.
 10. A taxi meter as claimed in claim 9 including presetand reset pulse generator means which operate to reset said counter anddisplay means when the taxi meter is switched on.
 11. A taxi meter asclaimed in claim 10, wherein said preset and reset pulse generator meansincludes preselector means for causing at least one flagfall counter ofsaid counter and display means to operate associated display means ofthe counter and display means to display a predetermined fare indicationupon switching on of the taxi meter.
 12. A taxi meter as claimed inclaim 11, wherein at least one of the said counters is provided withbinary coded input terminals which can be selectively coupled to apresetting pulse generator indluded in said preset and reset pulsegenerator means to cause said at least one flagfall counter to generatean output resulting in display, in the associated display means, of saidpredetermined fare indication.
 13. A taxi meter as claimed in claim 12,wherein said presetting pulse generator comprises means to generate apreset pulse, as the taxi meter is turned on, and said preselector meansincludes electric connector means on a removable plug-in board whichcouples selected ones of said binary coded input terminals to receivesaid preset pulse.
 14. A taxi meter as claimed in claim 13 wherein saidremovable plug-in boards are formed as a single unit.